Hydraulic drive for grinding machines



Dot. 9, 1934. s s 1,976,122

HYDRAULIC DRIVE FOR GRINDING MACHINES .Filed Jan. 7. 1930 4 Sheets-Sheet 1 anal/"e1 Oct. 9, 1934. F. s. HAAS HYDRAULIC DRIVE FOR GRINDINGMACHINES Filed Jan. 7, 1930 5 4 .m w W J m 3 2 W 0,, \R E: 1 4% A I??? v mw Q l g a Kw Q%% 8% a dual/neg Oct. 9, 1934. s s

HYDRAULIC DRIVE FOR GRINDING MACHINES 4 Sheets-Sheet 3 Filed Jn} 1930 Ivy/Ill gwumtoz $11 wtam Oct. 9, 1934.

F. S. HAAS HYDRAULIC DRIVE FOR GRINDING MACHINES Filed Jan. 7, 1930 4 Shets-Sheet 4 Patented Oct. 9, 1934 PATENT OFFICE HYDRAULIC DRIVE FoR GRINDING MACHINES Frederick S. Haas, Cincinnati, Ohio, assignor to Cincinnati Grinders Incorporated, Cincinnati, Ohio, a corporation of Ohio Application January 7, 1930, Serial No. 419,177

12 Claims.

This invention relates to improvements in machine tools and especially to improvements in machines having a translatable member.

An object of the invention isto provide in a machine tool organization, improved means for effecting and controlling the translation of one member thereof relative to its support.

Another object of the invention is to provide in a machine tool, improved hydraulic means having universal application for translating with equal facility either long or short members relative to their supports.

A further and specific object of the invention is to provide in a grinding machine, improved hydraulic means for controlling and translating the work supporting table or member thereof.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification, considered in conjunction with the accompanying drawings forming a part thereof, and it is to be understood that many modifications may be made in the specific structural details hereinafter disclosed, within the scope of the appended claims,

without departing from or exceeding the spirit of the invention.

In the drawings:

Figure 1 is a front elevation of a grinding machine embodying the improvements of this invention;

Figure 2 is a fragmentary sectional View taken on line 2-2 of Figure 1;

Figure 3 is a view taken on line 33 of Figure 2;

Figure '4 is a sectional view taken on line 4-4 of Figure 3;

Figure 5 is a sectional view taken on line 5-5 of Figure 3;

Figure 6 is a sectional view taken on line 6-6 40 of Figure 3;

Figure 7 is a view on line 7-7 of Figure 2;

Figure 8 is a perspective view of the gears of the hydraulic motor forming a detail of the invention; and

Figure 9 isa diagrammatic view illustrating the hydraulic circuit for efiecting and controlling translation of the work table.

Throughout the several views of the drawings, similar reference characters are utilized to indicate similar or corresponding parts.

In general, a device to which this invention may be applied comprises a bed 10 having ways 11 formed thereon for supporting a work table 12 for translation longitudinally thereof. The table 12 supports the usual power driven headstock 13 and tailstock 14, for supporting a work piece 15 therebetween and presenting same to a grinding wheel 16 mounted on one end of a spindle suitably journaled in bearing 17. The table 12 and grinding wheel 16 are adapted to be 60 actuated toward and from one another for effecting a stock removal from the work piece. Any suitable means may be employed for so actuating these parts. g

The table 12 is adapted to be reciprocated or 5 translated longitudinally of the bed by both power and manual means. Heretofore it has been customary to utilize hydraulic pressure as the power means for reciprocating the table 12 but this means has been in the nature of a 7n cylinder and piston contained therein, one or the other ,being supported by and movable with. the table, while the other is stationary and supported by the bed. However, when relatively long beds were utilized, difficulty was encountered in obtaining and properly machining a cylinder of sufiicient length to aiford the proper translation of the table. This was especially true when a machine having a table travel of eighteen feet or upward, was required. By so the improved hydraulic means disclosed in this application, these difficulties for hydraulically translating the table have been overcome, since no piston and no cylinder areutilized for eifecting the said translation.

The means here disclosed for effecting this translation comprises a hydraulic motor 18 of the twin gear type having a pair of gears 19 and 20. While it is possible to use gears in the hydraulic motor 18, of a type other than those shown herein, it has been found that herringbone gears of a heavy pitch give the best results. By using the herringbone gears there is no tendency for them to bind on the sides of their housing while under the influence of the hydraulic medium, since the inclined or angular surface of the teeth is toward the center of the gear, tending at all times to centralize the gears during their rotation. Also'the teeth of these gears more closely engage one another, thereby'reducing to a; minimum loss of power and greatly increasing the efiiciency of themotor. The gears 19 and 20 are illustrated most clearly in Figure 8 and each comprises a relatively few number of teeth 20a of a heavy or large pitch with their operative surfaces 20b and 200 tapering from a center line 20d outward to the outside surfaces thereof and forming an obtuse angle, with line 2001 as the apex. The gears 19 and-20 are enclosed in a housing or casing 23 and each has secured thereto a shaft 21 and 22. Stub shaft 22 is provided with a counterbore 24 forming a bearing for the main drive or countershaft 25, and the counterbore 24 has secured therein a suitable bushing 26 in which the reduced end 27 of the shaft 25 is rotatably journaled. The inner end of stub shaft 22 is provided with a flange 28 in which clutch teeth 29 are formed for engagement with clutch teeth 30 carried by gear 31. This gear 31 is slidably splined on the shaft 25 and has a. circumferential groove 32 formed in a hub 33 integral therewith, and a shifter fork 34 is received in the circumferential groove 32 for shifting the gear 31 to various positions. The fork 34 is carried by a rock shaft 35, which in turn is connected by arm 36 with one end of link 37. The other end of the link 37 is pivotally connected to a pin 38 mounted eccentrically in head 39 of shaft 40. Shaft 40 extends through the side wall 41 of control box 42 and has pinned, or otherwise secured thereto, a shift lever 43. The lever 43 is mounted exteriorly of the bed 10 in convenient reach of the operator.

From the foregoing description it will be noted that by shifting lever 43, a direct connection between drive shaft 25 and gear 20 of the pump 18 may be established for rotating the shaft 25 at the same speed as the gears 19 and 20 are rotated.

As shown in the drawings, gear 31 is in engagement with pinion 44 formed on the end of stub shaft 21 for effecting .a rotation of shaft 25 at a slower speed, since the pinion 44 is con- ,siderably smaller in diameter than gear 31 and will consequently rotate considerably faster. The same manual shift lever 43 is utilized for disengaging the teeth of pinion 44 and gear 31 and is also employed for shifting the gear to the position shown in dotted lines in Figure 6, at which time power is disconnected from drive shaft 25.

A suitable oil pump 45 is employed for circulating the hydraulic medium contained in tank 46, from which the medium is drawn off through conduit 47 and passed through to main pressure line 48. Conduit 48 has a pair of branch lines, one line passing through starting and stopping valve 49 while the other line goes through the rapid traverse valve 50. The hydraulic medium, after passing through starting and stopping valve 49, goes through reversing valve 51 through the conduit 52 to one side of the hydraulic motor 18. As shown in Figure 9, the hydraulic medium passes through conduit 53 to the lower side of the motor 18, from which the fluid passes back through conduit 54, reversing valve 51, conduits 55 and 56, to be returned to the reservoir or tank 46. By shifting reversing valve 51 to the right, as seen in Figure 9, conduit 52 will be connected through the valve 51 to conduit 54 for causing the hydraulic medium to enter the motor 18 at the upper end thereof, to effect a reverse rotation of the said motor 18, and the conduit 53 will then be connected with conduit 57 for conveying the hydraulic medium to conduit 56, for returning same to the tank 46.

Thus, by reversing the rotation of gears 19 and 20, driven shaft 25 may be reversely driven for effecting reverse translation of the work table 12 through transmissions to be later described.

A needle or other speed control valve 58 may be placed in the conduit 48 to control the rate of flow of the hydraulic medium through the said conduit 48 and, consequently, to control the speed at which the hydraulic motor 18 is rotated. This speed control valve 58 may be adjusted by handle or knob 581:. secured to the stem 58b thereof. Should it be desired to rapidly traverse the table for any reason, it is only necessary to depress the plunger 59 of valve 50 by manually shifting lever 91 mounted on the outer surface of the bed 10, thereby removing the valve head 60 from its seat against the yielding resistance of spring 61, to open the valve. This would allow a direct flow of the hydraulic medium from the conduit 48 through branch conduit 62 to the valve 50, then through conduit 63 to conduit 52. It will be noted that this branch conduit 62 is ahead of the speed control valve 58 and the flow of the fluid' through said conduit 62 would not be affected by the said speed control valve 58.

The shifting of the starting and stopping valve 49 is effected through manual shift lever 64, which has keyed, or otherwise secured, to it a plate 65 provided with means co-operating with spring pressed detent 65a to lock the lever in its operative positions, and the plate has depending therefrom a tongue 66 secured to the stem 67 of the valve 49. The shaft 68 of the lever 64 has pinned, or otherwise secured, thereto a switch arm 69 carried by a sleeve or bushing '70. The switch arm 69 is adapted to engage and close starting and stopping switches 71 and 72 respectively, which are electrically connected with the motor 73 of the power driven headstock 13. From this it will be noted that when the lever 64 is actuated to the left, as seen in Figure 1, for shifting the valve 49 to initiate a translation of the table 12, the starting switch 71 for the headstock 13 is automatically closed to start the rotation thereof and consequently the work carried thereby.

The shifting of the reverse valve 51 may be accomplished either automatically or manually through the reverse lever 74, which is keyed, or otherwise secured to a shaft 75 having depending therefrom a link 76, which has at its opposite end a lost motion connection, as at 77, with a link '78 secured to or carried by the reverse valve 51. The lever '74 is provided with an abutment extending toward the table 12 and adapted to be engaged by dogs 79 and 80 to shift same and consequently change the direction of movement of table 12 at each end of the stroke. Suitable means are provided for locking valve 51 in each of its positions, as well as to insure a proper shifting thereof at a definite time. This means includes what may be termed a load and fire mechanism comprising a dog 81 having a point 82 co-operating with notches 83 and 84 formed in one arm 85 of bell crank 86. Bell crank 86 is mounted to oscillate about pivot 87 and has its other arm 88 abutting spring pressed plunger 89 mounted within a boss 90 integral with the side wall of control housing 42. The operation of the control mechanism is such that, as the reverse lever 74 is being actuated by either of the dogs 79 or 80, the load and fire dog 81 is slowly'rising up the inclined edge e of notch 83 or 84 until the point 82 thereof passes the apex between notches 83 and 84.

fired and thereby forces bell crank 86-about its pivot 87, and inclined edge of notch 83 or 84 forceably shifts load and fire dog 81 and shaft 75 to rapidly shift the reverse valve 51 to its reverse position.

To effect a rapid traverse movement of the table, as was mentioned above, plunger 59 is depressed to remove valve head 60 from its seat. This is accomplished through the lever 91 journaled in the front of control housing 42 and provided with a shaft 92 which has pinned, or otherwise secured, to it a lever 93 in such a position as to engage the plunger 59 when the lever 91 is actuated.

From the foregoing description it will be understood how the gears 19 and 20 of by draulic motor 18 are rotated and how the rotation thereof is reversed and controlled as to speed. This rotation of the gears 19 and 20 is transmitted to the table 12 through the driven shaft 25 which has secured thereto a Worm 94 meshing with a Worm wheel 95 loosely mounted on pinion shaft 96. The worm wheel 95 is also provided with clutch teeth 97 for engagement with clutch teeth 98 formed on clutch spool 99 slidably keyed to pinion shaft 96 so as to rotate ,therewith. Clutch spool 99 is provided on its opposite end with clutch teeth 100 adapted to engage clutch teeth 101 formedon beveled gear 102 loosely mounted on sleeve 103 which surrounds the pinion shaft 96 and is carried by the bed 10. The clutch spool 99 is further provided with a circumferential groove 104 for reception of shifter fork 105. The pinion shaft 96 carries at its upper end a pinion 106 in mesh with the teeth 107 of rack 108 secured to the under side of the table 12.

, It will now be seen that rotation of drive shaft 25 is, through intermeshing of worm 9i, worm wheel 95 and clutchspool 99, transmitted to pinion shaft 96 and, consequently, through pinion 106 and rack 108 to effect the translation of table 12.

As was mentioned above, table 12 may be power or manually reciprocated and the'power means therefor having been described, the manualmeans will now be described. Asshown in Figure 2, the table 12 is .illustrated so as to be translated by the manual means and to this end bevel gear 102 is utilized, it meshing with a bevel pinion 109 on the end of shaft 110. A drive gear 111, carried by the shaft 110, has extending thereabout silent chain 112 which likewise extends about gear 113. Gear 113 is provided with a sleeve, to which hand wheel 114 is keyed, or otherwise secured, for rotadzing same, and has a shaft 115 extending therethrough for suitably supporting it in the walls of the control casing 42. By reference to Figure 2 it will be noted that the portion 115a of shaft 115 is eccentric to the remainder of the shaft. This eccentric portion 115a forms a bearing for the shaft about which the axis of the remaining portion of the shaft may be actuated to vary the distance between the axes of shaft 115 and shaft 110 to properly tension the silent chain 112 so that the proper engagement is had between the said chain and the gears 111 and 113. 1

To disconnect the clutch spool 99 from the bevel gear 102 and to consequently disconnect the manual reciprocating means, shifter fork 105 is provided with an arm 116 having a pin 117 extending into a slot 118 between arms 119 and 120 of link 121. Link 121 is secured to a on the outside surface of control box 42. The

shaft 122 has secured to its other end a manualshift lever 124 for oscillatably actuating the same and, consequently, the link 121 carried thereby. It will be apparent that if lever 124 were actuatedaway from the bed 10, a counterclockwise movement would be imparted to link 121 and a clockwise movement to lever 116 for actuating same about its pivot 125 and thereby shifting clutch spool 99 away from bevel gear 102 toward worm wheel 95. Means are provided for locking the clutch spool 99 in its various positions, viz., when in engagement with bevel gear 102, when in engagement with worm wheel 95, and when in a neutral position intermediate these two, and to this end, arm 116 is provided with a spring' pressed plunger 126 co-operating with notches 127 formed in the face of plate 128 secured to the inner wall of control casing 42.

What is claimed is:

1. In a machine tool organization the combination of a support, a member for translation thereover, hydraulic means for effecting said translation including a hydraulic gear motor, a hydraulic medium for effecting the rotation of said gears, a shaft operatively connected with each gear, a transmission gear carried by. one of the shafts, a second transmission gear slidably carried by the other shaft and bearing a ratio to the first transmission gear different from the ratio between the motor gears, means for operatively connecting the sliding transmission gear with the motor and with the first transmission gear, and means operated by the sliding gear for translating the member at.rapid and feeding rates.

2. In a machine tool organization the combination of a support, a member translatably carried thereby, a hydraulic motor comprising.

necting the slidable transmission gear with the other transmission gear and with the second gear of the motor whereby the shaft is driven at different speeds, and means operatively connecting the driven shaft with the member for translating same.

3. In a machine tool organization the combination of a support, a member translatably carried by the support, a hydraulic twin gear motor, means operatively connecting the motor with the member for translation thereof, a hydraulic medium for rotating the motor gears, a conduit for the medium, means for controlling the flow of the medium through the conduit to control the rotation of the motor and rate of translation of the member, means by-passing the last mentioned means for effecting a rapid rotation of the gears and rapid translation of the table, and additional means for varying the.

means for controlling the rate of supply and therefore the rate of rotation of the impeller to effect a translation of the member at a feeding rate, and means remote from the feed controlling means by-passing the same to effect a translation of the members at a rapid traverse rate.

5. In combination witha translatable member, of hydraulic means including a rotatable impeller for translating the member, transmission means between the impeller and the member, means for connecting and disconnecting the impeller and transmission means, means for reversing the rotation of the impeller to effect reverse translation of the member, adjustable means for controlling the rate of supply and therefore the rate of rotation of the impeller to efi'ect a translation of the member at a feeding rate, and means remote from the-feed controlling means by-passing the same to effect a translation of the members at a rapid traverse rotation of the motor and consequently translating the member at a rate corresponding to the rate of the motor, and means on the other motor gear shaft for driving the driven shaft at a rate other than that representative of the rate of the motor gears to correspondingly translate the member.

I. In a, machine tool organization the combination of a bed, a member carried thereby and translatable relative thereto, and means for translating said member includinga hydraulic motor of the twin gear type, a shaft for each gear, a driven shaft, a rack and pinion connection between the driven shaft and the member, means connecting the-driven shaft with one of the motor gear shafts for driving the said driven shaft at a rate corresponding to the rate of rotation of the motor and consequently translating the member at a rate corresponding to the rate of the motor, means on the other motor gear shaft for driving the driven shaft at a rate other than that representative of the rate of the motor gears to correspondingly translate the member, and means for varying the rate of rotation of the motor to correspondingly vary the rate of translation of the member.

8. In a machine tool organization the combination of a bed, a member carried thereby and translatable relative thereto, and means for translating said member including a hydraulic motor of the twin gear type, a shaft for each gear,'a driven shaft, a rack and pinion connection between the driven shaft and the member,

means connecting the driven shaft with one of the motor gear shafts for driving the said driven shaft at a rate corresponding to the rate of rotation of the motor and consequently translating the member at a rate corresponding to the rate of .the motor, means on the other motor gear shaft for driving the driven shaft at a rate other than that representative of the rate of the motor gears to correspondingly translate the member, means for varying the rate of rotation of the motor to correspondingly vary the rate of translation of the member, and additional means for reversing the direction of rotation of the motor gears and the direction of translation of the member.

9. In a machine tool organization the combination of a reciprocating member, a hydraulic motor of the twin gear type, a driven shaft, a rack and pinion transmission line between the driven shaft and member, one of the motor gears having a clutch associated therewith, the other motor gear having a pinion connected therewith, and a sliding gear clutch for engagement with either the motor clutch or motor pinion and bearing a ratio to the second pinion difierent from the ratio between the motor gears whereby the member is translated at different rates independent of the rate of rotation of the motor.

10. In a machine tool organization the combination of a reciprocating member, a rotatable shaft having an operative connection with the member, manual means connectable with the shaft and including a bevel gear loosely surrounding the shaft, a worm, a hydraulic motor for rotating said worm, a worm wheel adapted to be driven by the worm and loosely surrounding the shaft, a clutch carried by the shaft for rotative movement therewith and for axial movement independently thereof, and means for shifting the clutch into. engagement with either the bevel gear or worm wheel to connect the member for manual or power actuation.

11. In a machine tool organization the combination of a bed, a member carried thereby and reciprocable relative thereto, a hydraulic motor connectable to the member for effecting said reciprocation, a hydraulic medium for actuating said motor, a conduit for the medium, means for starting and stopping a flow of the medium through the conduit, means independent of the starting and stopping means for reversing the flow of the medium through the conduit, and means for controlling the flow of medium to control the rate of actuation of the motor and manually actuated clutch means for connecting and disconnecting the motor and member at will. 12. In a machine tool organization the combination of a bed, a member carried thereby and. reciprocable relative thereto, a hydraulic motor connectable to the member for effecting said reciprocation, a hydraulic medium for actuating said motor, a conduit for the medium, means for starting and stopping a flow of the medium through the conduit, means independent of the starting and stopping means for reversing the flow of the medium through the conduit, means for controlling the flowof medium to control the rate of actuation of the motor, means bypassing the rate of'flow controlling means to change the said rate of flow of the medium, and means for connecting and disconnecting the motor and member.

FREDERICK S. HAAS. 

